It is not lawful for thee to have her - It was not lawful indeed for either of them to have her. For her father Aristobulus was their own brother. John's words were rough, like his raiment.He would not break the force of truth by using soft words, even to a king.

Being before instructed by her mother - Both as to the matter and manner of her petition: She said, Give me here - Fearing if he had time to consider, he would not do it: John the Baptist's head in a charger - A large dish or bowl.

And he sent and beheaded John in the prison, and his head was given to the damsel - How mysterious is the providence, which left the life of so holy a man in such infamous hands! which permitted it to be sacrificed to the malice of an abandoned harlot, the petulancy of a vain girl, and the rashness of a foolish, perhaps drunken prince, who made a prophet's head the reward of a dance! But we are sure the Almighty will repay his servants in another world for what ever they suffer in this.

The fourth watch - The Jews (as well as the Romans) usually divided the night into four watches, of three hours each. The first watch began at six, the second at nine, the third at twelve, the fourth at three in the morning. If it be thou - It is the same as, Since it is thou. The particle if frequently bears this meaning, both in ours and in all languages. So it means, 13:14 ,17. St. Peter was in no doubt, or he would not have quitted the ship.